High DC Ripple on VE.Bus System

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hersjoen asked Jan 6, '24

High DC Ripple on VE.Bus System

Hi!

For the past two days, I’ve been receiving multiple “High DC Ripple: Warning” messages followed by a recovery message a minute later. This is a new occurrence for my system, which has been running smoothly for a year. While I’m not on-site,

I suspect these warnings occur when the battery is full and the MPPT is charging. The system has a light load ( less than 100watt). I recently adjusted the battery settings on the smart shunt to address state of charge drift, following Victron’s recommendations for lithium. However, I couldn’t find a specific recommendation for the charged voltage for lithium, so I set it to 53.53V. What might be causing these warnings, and how can I resolve the issue?

System:

-SmartSolar Charger MPPT 150/35

- SmartShunt 500A

-MultiPlus-II 48/3000/35-32 (ACOut2 switchable)

-battery is 48v, 140ah lithium lifepo4.

Lithium Battery warnings ripple

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Answer 1 · 2024-01-06T15:26:20Z

Alexandra answered · Jan 06 at 03:26 PM

@Hersjoen

The usual suspects are the battery (connecting and disconnecting going into protection) and loose DC connections.

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hersjoen commented · Jan 07 at 03:08 PM

Hi Alexandra andThanks for your response!

I also suspect it's the BMS cutting off when the battery is fully charged. Shouldn't the MPPT shift to absorb before the BMS cuts in, though? I'm wondering if this is something normal that I just have to accept, or does it potentially impact the system's performance?

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Alexandra ♦ hersjoen commented · Jan 07 at 04:29 PM

No DC ripple is bad for the system. It can kill the power pack.

What battery exactly do you have the charged voltage should be set for what that manufacturer expects. Is it a 16s battery or a 15s battery?

Every manufacturer is different.

Pylontec bulk 52

Revov 54.8v

Blue Nova 55.5v

BYD 56.5v

There are vast differences.

You will need to adjust yours.

Use the shunt readings more than the ve bus ones right now. The ve bus can be higher if grid connected or processing loads.

How else is your inverter programmed? With ESS?

Do you have all the same voltages set everywhere?

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hersjoen Alexandra ♦ commented · Jan 16 at 08:46 AM

The battery has 16 cells.

The system is an off-grid system. The AC is connected to a generator but is only used manually.

The inverter (Multi) is set to battery monitor automatic, and it has automatically selected the data from the shunt.

I adjusted the charge voltage on the shunt down to 53V from 53.2V to see if it helps when the sun comes back. It has been cloudy for some days.

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